<!doctype html>
<head>
	<meta charset="UTF-8">
	<title>Document</title>
	<style>
		.red{color:Red;}
		.back{background:yellow;}
		.bigFont{font-size:48px;}
		.hide{display:none;}
	</style>
</head>
<body>
	<div id="main">
		测试的div内容
	</div>
	<button onclick="btnClick()">样式操作</button>
	<script src="jquery-1.11.3.js"></script>
	<script>
		function btnClick(){
			//$("#main").attr("class","bigFont back red");

			//$("#main").addClass("bigFont").addClass("back").addClass("red");

			$("#main").toggleClass("hide");
		}
	</script>
</body>
</html>